Research into the amelioration of mental health problems of siblings of chronically ill/disabled children is essential to control future morbidity. Reports indicate that up to 26 percent of siblings of children with chronic illness develop mental health or behavior problems. Other studies have suggested that as many as 29 percent of U.S. children suffer from some moderate to severe chronic illness. If these numbers are accurate, they imply that mental health or behavior problems associated with being a sibling of a chronically ill child are quite prevalent. Perhaps as many as 4-6 percent of all American children suffer from such problems. The general aim of the proposed study is to investigate the effects of an intervention for siblings of children with chronic illness, using a randomized, three-group, repeated measure, experimental design. The baseline and post intervention phases will document the siblings levels of knowledge of illness, self-esteem, social support, mood and behavior problems, outcomes shown in the literature to be sensitive to change in pediatric intervention studies. Also, documented are factors in the family and the care giving environment (family cohesion, impact of illness on the family, family socioeconomic status as indicated by mother s education, maternal mood, and age grouping of the well sibling). The intervention phase uses a randomized clinical trial. It is designed a) to allow siblings some respite from a chronically stressful home situation, enrich the siblings experiences with organized social activities and peer friendships; impart knowledge, discuss psychosocial issues, and promote social support, self-esteem, and positive mood; and b) to maintain these gains over time by enhancing parental awareness of sibling needs. The intervention enables siblings to participate in nurse-guided, structured educational and peer support group sessions which allow clarification and sharing of information, questions, concerns, and coping skills related to the ill child's disability. One group of siblings (TG1, n=100) will receive the above intervention at a residential camp. A second group of siblings (TG2, n=100) will attend camp without the above intervention. A third group (CG, n=120), a waiting list control group, will attend camp upon completion of all measurement time points. Measurement points for all three groups occur at baseline (01), immediately after intervention (02), 4 months after the point (03), and again at 9 months (04) and at 12 months (05) after the intervention. For TG1, at 4 and 9 months following data collection, "booster" sibling and parent sessions will be held. The major purposes of the proposed study are 1) to test whether the experimental intervention results in a significant change in sibling knowledge about illness, sibling social support, self-esteem, mood, and behavior problems immediately after camp and 4 months after, and 2) to test whether treatment effects are maintained over time, at 9 months and at 12 months. The testing of four primary hypotheses will be done using ordinary lest squares regressions to control for the influences of 5 covariates and baseline values. This procedure is equivalent to an ANCOVA design, but it assures that adequate power will be achieved at the sample sizes available for this study. As a follow-up on the intervention, the "insider viewpoint" on "what worked or did not work" will be examined qualitatively.